When the cpu is powered down in a low power mode, the vfp
registers may be reset.

This patch uses CPU_PM_ENTER and CPU_PM_EXIT notifiers to save
and restore the cpu's vfp registers.
Signed-off-by: NColin Cross <ccross@android.com>
Signed-off-by: NSantosh Shilimkar <santosh.shilimkar@ti.com>
Reviewed-by: NKevin Hilman <khilman@ti.com>
Tested-and-Acked-by: NShawn Guo <shawn.guo@linaro.org>
Tested-by: NVishwanath BS <vishwanath.bs@ti.com>